1. Field of the Invention
The present invention relates to semiconductor device planarization technology in the field of semiconductor device manufacturing.
2. Description of the Related Art
In semiconductor device manufacturing, an abrasive composed of cerium oxide (CeO2) particles has been used for polishing an insulating film, particularly in CMP (Chemical Mechanical Polishing) for forming STI (Shallow Trench Isolation). In this case, a surfactant is added to disperse the cerium oxide particles. The degree of dispersion is adjusted by the type and amount of surfactant.
However, dispersion can become cohesion, depending upon the amount of surfactant added. The amount of surfactant is sometimes intentionally increased in order to enhance the effect of planarization. But, this induces cohesion of the cerium oxide particles. This causes scratches on the insulating film surface. Further, a high amount of surfactant will lower the polishing rate, and decrease the throughput in a polishing process.